This invention relates generally to the protection of stacked lumber from damage due to weather, etc., during shipment, and more particularly to a method of and apparatus for protecting stacked lumber which incorporate numerous advantages over the prior art.
2xc3x974""s, 2xc3x976""s, 2xc3x978""s, plywood, and similar lumber products are typically arranged in stacks for shipment from the manufacturer to lumber yards, hardware stores, contractors, etc. Stacks of lumber are typically wrapped in plastic sheeting during transport. The plastic wrapping protects the lumber from exposure to the elements and also provides a convenient place to identify the manufacturer of the lumber.
In a typical application, plastic sheeting covers all four sides and the top, but not the bottom, of a lumber stack. Heretofore two methods have been used to wrap lumber stacks with plastic sheeting. One method is to wrap a lumber stack with an appropriately sized plastic sheet in the same manner that a rectangular package is wrapped for shipping or as a gift. Another method is to use an envelope-like construction comprising a plastic sheet with is folded in half longitudinally and sealed at the ends. The resulting construction is utilized by separating the plastic layers at the open side of the envelope, fitting the envelope over a lumber stack, then folding the ends of the envelope downwardly.
Regardless of which of the foregoing procedures is utilized to wrap a lumber stack in plastic sheeting, it has heretofore been the practice to secure the plastic sheeting to the lumber stack by stapling the plastic sheeting to the lowermost layer of lumber in the stack at spaced apart intervals around the entire periphery of the stack. The use of staples to secure plastic sheeting to a lumber stack is disadvantageous for at least two reasons. First, the staples can severely damage the lumber into which they are inserted. Second, the stapling procedure is time consuming and therefore expensive.
The present invention comprises a method of and apparatus for securing protective plastic sheeting around stacked lumber which overcomes the foregoing and other difficulties which have long since characterized the prior art. In accordance with the broader aspects of the invention, the plastic sheeting that is utilized in the protection of stacked lumber comprises heavy duty shrinkwrap plastic material. The heavy duty shrinkwrap plastic material is positioned around a lumber stack. Thereafter, the portions of the heavy duty shrinkwrap material which are located at the ends of the lumber stack are heated. In this manner, the heavy duty shrinkwrap material is drawn tightly around the lumber stack and is secured thereto without the use of multiple staples.
In accordance with more specific aspects of the invention, a layer of heavy duty shrinkwrap plastic material is closely fitted around a lumber stack. The portions of the heavy duty shrink wrap plastic material which engage the ends of the lumber stack are initially secured in place by as few as two staples. Thereafter, the portions of the heavy duty plastic shrinkwrap material which engage the ends and the corners of the lumber stack are heated, thereby securing the heavy duty plastic shrinkwrap material securely to the lumber stack particularly at the corners. Optionally, the portion of the heavy duty plastic shrinkwrap material which extends across the top of the lumber stack may also be heated resulting in a smooth, upper surface.
In accordance with another aspect of the invention, an appropriately sized sheet of heavy duty plastic shrinkwrap material is folded along spaced apart longitudinally extending lines and is sealed at the ends. The resulting construction is characterized by a solid upper layer and a lower layer having an opening extending longitudinally along the center thereof from one end to the other. The plastic sheeting construction of the present invention is much easier to install around a lumber stack as compared with the envelope of the prior art in which the opening extends along the side edges of spaced apart plastic layers. Additionally, when the plastic sheeting construction of the present invention is installed around a lumber stack, the end portions thereof are formed into a rectangular flap which is easily secured in place by two staples at each end of the lumber stack.